Sample records for khellin
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Kamal, Abid; Khan, Washim; Ahmad, Sayeed; Ahmad, F. J.; Saleem, Kishwar
2015-01-01
Objective: The present study was used to design simple, accurate and sensitive reversed phase-high-performance liquid chromatography RP-HPLC and high-performance thin-layer chromatography (HPTLC) methods for the development of quantification of khellin present in the seeds of Ammi visnaga. Materials and Methods: RP-HPLC analysis was performed on a C18 column with methanol: Water (75: 25, v/v) as a mobile phase. The HPTLC method involved densitometric evaluation of khellin after resolving it on silica gel plate using ethyl acetate: Toluene: Formic acid (5.5:4.0:0.5, v/v/v) as a mobile phase. Results: The developed HPLC and HPTLC methods were validated for precision (interday, intraday and intersystem), robustness and accuracy, limit of detection and limit of quantification. The relationship between the concentration of standard solutions and the peak response was linear in both HPLC and HPTLC methods with the concentration range of 10–80 μg/mL in HPLC and 25–1,000 ng/spot in HPTLC for khellin. The % relative standard deviation values for method precision was found to be 0.63–1.97%, 0.62–2.05% in HPLC and HPTLC for khellin respectively. Accuracy of the method was checked by recovery studies conducted at three different concentration levels and the average percentage recovery was found to be 100.53% in HPLC and 100.08% in HPTLC for khellin. Conclusions: The developed HPLC and HPTLC methods for the quantification of khellin were found simple, precise, specific, sensitive and accurate which can be used for routine analysis and quality control of A. visnaga and several formulations containing it as an ingredient. PMID:26681890
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Khellin and Visnagin, Furanochromones from Ammi visnaga (L.) Lam., as Potential Bioherbicides.
Travaini, Maria L; Sosa, Gustavo M; Ceccarelli, Eduardo A; Walter, Helmut; Cantrell, Charles L; Carrillo, Nestor J; Dayan, Franck E; Meepagala, Kumudini M; Duke, Stephen O
2016-12-21
Plants constitute a source of novel phytotoxic compounds to be explored in searching for effective and environmentally safe herbicides. From a previous screening of plant extracts for their phytotoxicity, a dichloromethane extract of Ammi visnaga (L.) Lam. was selected for further study. Phytotoxicity-guided fractionation of this extract yielded two furanochromones, khellin and visnagin, for which herbicidal activity had not been described before. Khellin and visnagin were phytotoxic to model species lettuce (Lactuca sativa) and duckweed (Lemna paucicostata), with IC 50 values ranging from 110 to 175 μM. These compounds also inhibited the growth and germination of a diverse group of weeds at 0.5 and 1 mM. These weeds included five grasses [ryegrass (Lolium multiflorum), barnyardgrass (Echinocloa crus-galli), crabgrass (Digitaria sanguinalis), foxtail (Setaria italica), and millet (Panicum sp.)] and two broadleaf species [morningglory (Ipomea sp.) and velvetleaf (Abutilon theophrasti)]. During greenhouse studies visnagin was the most active and showed significant contact postemergence herbicidal activity on velvetleaf and crabgrass at 2 kg active ingredient (ai) ha -1 . Moreover, its effect at 4 kg ai ha -1 was comparable to the bioherbicide pelargonic acid at the same rate. The mode of action of khellin and visnagin was not a light-dependent process. Both compounds caused membrane destabilization, photosynthetic efficiency reduction, inhibition of cell division, and cell death. These results support the potential of visnagin and, possibly, khellin as bioherbicides or lead molecules for the development of new herbicides.
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Khellin and visnagin, furanochromones from Amni visnaga (L.) Lam., as potential bioherbicides
USDA-ARS?s Scientific Manuscript database
Plants constitute a source of novel and structurally diverse phytotoxic compounds to be explored in searching for effective and environmentally safe herbicides. From screening nearly 2400 plant extracts for their phytotoxicity, a dichloromethane extract of Ammi visnaga (L.) Lam. was selected for fur...
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Kinley, J S; Moan, J; Dall'Aqua, F; Young, A R
1994-07-01
We report quantitative data on epidermal melanogenesis by established and new furocoumarins. The ears and dorsal skin of pigmented hairless mice were treated for 12 d with compounds in ethanol, at equi-optical concentrations, and exposed to subphototoxic doses of ultraviolet A. Increased pigmentation was observed with 6,4,4'-trimethylangelicin > psoralen > 8-methoxypsoralen > 5-methoxypsoralen > 4,4',5'-trimethylazapsoralen = bergamot oil. Assessment of melanocyte numbers and morphology in epidermal sheet dihydroxyphenylalanine preparations showed that 6,4,4'-trimethylangelicin was the best compound with 536 ear melanocytes/mm2 +/- 15 SEM compared with 46 +/- 4 in controls. Psoralen induced 297/mm2 +/- 33, compared with its methoxy derivatives with ranges between 200 and 240/mm2.6,4,4'-trimethylangelicin had a striking effect on dorsal skin with 462 +/- 18 melanocytes/mm2 compared to less than 80/mm2 in all other ultraviolet A treatment groups. Khellin, 5-GOP and ultraviolet A only and all non-ultraviolet A controls had no effect. Melanogenesis was associated with increased dendricity, melanocyte size, especially with 5-methoxypsoralen, and giant melanocytes were noted with some treatments. The potency of 6,4,4'-trimethylangelicin, which does not form DNA interstrand crosslinks, may be related to its high DNA binding constant. Our data may be useful in the selection of compounds to treat vitiligo.
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Topical treatment and combination approaches for vitiligo: new insights, new developments.
Hossani-Madani, A R; Halder, R M
2010-02-01
Despite much research done involving elucidation of the pathogenesis of vitiligo, a precise cause is still not known. Prevalent hypotheses include the autoimmune, genetic, neural, self-destruction, growth factor deficiency, viral, and convergence theories, which have served as the basis for treatment formulation. Topical therapies have been a mainstay of vitiligo treatment, with or without phototherapy. Topical treatments used in the treatment of vitiligo include steroids, calcineurin inhibitors, vitamin D analogues, pseudocatalase, and depigmenting agents. Combination therapies are used to improve the success rate of repigmentation. In this article, we have examined randomized controlled trials utilizing topical treatments used as monotherapy or combination therapy. Although psoralen and khellin can be used as topical agents, used in conjunction with UV radiation, we have not included them in the review due to their inability to be used as monotherapy. We have also excluded less used or ineffective topical agents, such as melagenina, topical phenylalanine, topical L-DOPA, coal tar, anacarcin forte oil and topical minoxidil. According to current guidelines, a less than two month trial of potent or very potent topical corticosteroids or topical calcineurin inhibitors may be used for therapy of localized vitiligo (<20% skin surface area). Combinations of topical corticosteroids with excimer laser and UVA seem to be more effective than steroids alone. Pseudocatalase plus NB-UVB does not seem to be more effective than placebo with NB-UVB. Combinations of vitamin D analogues have varied efficacy based on which type is used and the type of UV light. Efficacy of calcineurin inhibitor combinations also vary based on the type used and UV light combined, with tacrolimus being more effective with excimer laser. Pimecrolimus has been effective with NB-UVB and excimer laser on facial lesions, and microdermabrasion on localized areas.